What is an slot on a motherboard used for?

What is an slot on a motherboard used for? m2 expansion slot My ten year old PC uses DDR3 memory and PCIe expansion slots, the x16 slot is occupied by the graphics card, no slot on the motherboard m2 pcie slot 2 is a specification for internal expansion cards on PC mainboards and notebook computers Suitable for slot with key M or B+M based on PCIe Chipset:

m2 slot screw It is a specification for internally mounted computer expansion cards and associated connectors Look for an option related to the PCI Express slot Check